Re: OS map To LL - where is the top left of a map.

Here is a suggestion that should give crude coords, assuming I understand
your problem.

Go to an index such as http://www.watsonlv.addr.com/50k_map.htm
This is set up to respond to mouse over events (my terminology might not be
quite right) so that if you hover the mouse over the map the link (shown in
the task bar of IE) changes depending on the location of the cursor.
Hovering the mose around over the map shows this to be set up with a
reasonable level of accuracy.

If you "View|Source" (on IE) you will see the html containing the area
coords of each map ***, e.g.
<area coords="410,7,438,35" title = "*** 1: Shetland, Yell, Unst & Fetlar"
alt= "*** 1: Shetland, Yell, Unst & Fetlar" href="50k_list.htm#1">

I assume these are pixel coords relative to the map image. It should be
reasonably straightforward to paste the html in a spread*** and parse the
text to extract the coords and map *** number. Given the known full grid
references (with numeric 100,000 qualifier) of the bounds of a couple of
sheets you should then be able to do a translation to convert the pixel
coords to full OS grid references. You can then use a simple lookup to
convert the 100,000 prefix to the two letter prefix if you need.


"Tony Jay" <tony.jay@xxxxxxxxxxxxxxx> wrote in message
news:433faad4$0$16345$ed2619ec@xxxxxxxxxxxxxxxxxxxxxxxxxxxxx
>I have a list of OS coordinate ie
>
> map 164, 491291 (1:50000 maps)
>
> which I am trying to convert to Lat long (to import into google earth)
>
> If I look on the map this is SP491291 (which I can trivially convery to
> LL)
>
> The problem is that I have about 30000 points (and they are being created
> every week). I can not get the creator to append the two letter code as
> they only work on paper maps, so do not care about the exact position (and
> it would be a tedious task)
>
> Fortunately a numeric position is unique on a 1:50000 paper map.
>
> What I need is know the top left corner position (in either LL or 8,10,12
> os gb references) of every map.
>
> Or does some one have a better idea (go to the local library and write
> them all down !)
>
> Thanks
>
> Tony
>


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